Fuel and air control for industrial stoker drives



FUEL AND AIR CONTROL FOR INDUSTRIAL STOKER DRIVES 3 Sheets-Sheet l R. C. WRIGHT EQA Feb. 3, 1953 Original Filed April 28, 1947 1953 R. c. WRIGHT 7, 38

FUEL AND AIR CONTROL FOR INDUSTRIAL STOKER DRIVES Original Fil ed April 28, 1947 s Sheets-Sheet 2 ji g.

Feb. 3, 1953 R. c. WRIGHT 2,627,238

FUEL. AND AIR CONTROL FOR INDUSTRIAL STOKER DRIVES Original Filed April 28, 1947 5 Sheets-Sheet 3 Patented Feb. 3, 1953 FUEL AND" CONTROL. EOR INDUSTRIAL STOKEB. DRIVES Richardfi; Wright, Bay Village, Ohio, assignor to Iron Fireman'Manufacturing-Company, Cleveland; Ohio Original. application. April,.28.,, 1.947,, SerialNm 744,392.. Divided and thisapplicationJanuary 19,1949; .SerialilNo. 71,661..

Claims. 1.

This is a divisional application ofSerial-No. 744392, filed April 28, 194.7, and now-U. S. Patent No. 2,578,650, issued December 11, 1951'.

This invention relates generally to industrial stoker drives and particularly to a fuel and air feed control for industrial stoker drives.

This invention has for its object the improvements in industrial stoker'drives .herein'set forth, which among other things include an improved planetary type. differential .speedreducer of. the V'-belt controlledcontinuously variable type; the general type of. which. is 'set forth in the wellknown Frenchpatentto M. Henri Mollard, Patent No. 804,694, issued October 29,1936.

More particularly, my invention provides an improved industrial stoker drive comprising in combination an improved planetary differential type speed. reducer, an improved V'be1t.and..expending sheaves control therefor and an improvedmeans. for synchronously controlling; the combustionfuelandair, thusproviding a novel unitary mechanism of; great utility which has previously been, lacking, inv this. field.

Itshould be. understood that astoker drive gear.- setis for. the purpose of reducing the. high rotating speed of the electric motor used to drive it to the very, low speed (say ofthe range of 0 to .20 R. P. M.).required to operate the coal feeding screw of the stoker. When a stoker transmission having one or more definite speeds available is used, settings of. the damper for control of combustion air canbeestablishedso that whenever the fuelrfeed is changed manually or otherwise, the companionair settingcanibemade manually .orotherwise. Butwitha continuously variable fueli feed transmission. as shown herewithit is. desirable to. provide a. continuously variable air, supply control to operate in synchronism with it. Providing such .a continuously variable. air control andcombining it with the fuel control for synchronous variation is another desirable object of this invention.

These and other objects are accomplished in the manner set forth. in the following specifications, as illustrated in the accompanying drawings, wherein:

Fig. l is a part sectional side view of my transmission,

Fig. 21s a sectional view of. my V-belt and expanding sheave control shown in side elevation on the right end of Fig. 1

Fig. 3 is a slieletonized view in perspective showing the mechanical scheme of my fuel feeding transmission.

Referring now to thedrawings; at lis'shown anelectric motor" assumed tobe connected to a power line (not shown) through a magnetic switch-(not shown). By means of V-belt*2 and sheaves 3 and 4, motor I drives the input shaft 5 on which is fixed worm 6 mating with worm gear 1 carried on differential ring gear 3 meshing with planet gears 9 rotatably supported on pins ill fixed in planet cage II -[2' to which is fixed concentric pinion I3 which meshes with gear l4 keyed to shaft It, to which is'pinned chain sprocket H which drives'chain sprocket l8 through roller chain 19. Sprocket I8 is secured to-the feed screw 20of the stoker coal feeding conveyor (not shown).

Sun pinion 2| keyed to shaft 22 rotates with worm gear '23 keyedto shaft 22. Worm gear 23 meshes with worm 24 on shaft 25 to which is secured the fixed half 25 and on which slides the movable half'Zl of an expanding sheavecoupled through V-belt 28' to another expanding sheave whose fixed half 29 is secured to shaft 5 and whose movable half 30 slides on shaft 5.

Shafts 5, I 6, Hand 25 are'carried on bearings in the housing 3| as shown. Ring gear 8 and planetcage I l|2 are rotatably carried on shaft 22as shown;

Rigidly secured to case 31 and parallel with shafts 5 and 25 is dead shaft 53 to which is rigidly secured at its outer end indicator plate 54 having at its upper end arcuate slot 55 and scale 56 to indicate the relative'speed of the output shaft of the transmission in terms of whatever use to which the transmission is put-in thisthe coal feed of the Stoker. Below the centerof 'indicatorplate 54 itis'perforated'by arouate slot 5] and carriesscale 53 for indicating and adjusting the air-fuel ratio of the stoker in a mannerto be described.

Axially slidable on dead shaft 53is hub 59 having cam. face 60 and carrying 2 frame Bl also guided on hub'62of case 3|. Around shaft 53 and abutting hubs 53 and 62 is compression spring 63 continuously urging Z frame and cam away from case, 3|. groove sheave 84 restrained in both axial and angular movement by lever arm 64 one end of which is journalled on shaft 53 and'whose other end carriesv stud 65. extending through slot 55in plate 54 to which arm 64 maybe clampedbyknob fifi'threaded onstud 65. Rotatably carried on studs 61in sheaves 84 are two diametrically opposed conical cam followers 68 Which, by the angular position of sheaves 84 orarm 64, determine the axial position of'lframetl. The ends of Z frame 61' aresecured respectively to the Journalledon shaft 53 is two-- outer races of ball bearings whose inner races are secured as shown to the hubs of movable half sheaves 21 and 30. Movable half sheaves 21 and 30 rigidly support pins 69 which slidably engage fixed half sheaves 25 and 29 causing movable half sheaves 21 and 30 to maintain constant angular relations with their respective fixed half sheaves 26 and 29.

Where a stoker supplies coal to a combustion chamber, air must also be supplied at a rate synchronized with the coal feed rate and the air supply may be through a fan driven separately from the coal feed drive or the fan 85 may be connected directly to the coal feed drive through shaft 5 as indicated in Fig. 3. In this case, as shown in Fig. 1, both ends of shaft 5 extend to the outside of case 3|, one end carrying drive and regulating sheaves and the other end carrying the fan wheel. But whenever the source of combustion air, the control will preferably be by an automatic air regulating damper mechanism of the type developed along the lines of U. S. Patents 2,116,912, 2,108,873 and 2,149,934. In these patents, it is shown that any desired rate of air feed for which the control is set will be strictly maintained and that the rate of air fed may be smoothly varied simply by varying the setting of the air rate indicating quadrant or lever of the air control. To synchronize such an air control with my present stoker drive, the setting arm or quadrant of the air control is biased by means of a spring or weight towards its less air limit and a tiller rope or cable is attached to the quadrant to move it against the force of the spring. This tiller rope or cable, guided by the necessary idler sheaves, is brought from the air control quadrant and approaches the transmission in the plane of groove Ill in sheaves 84.

Hinged on plate 54 by journal TI is air adjustment lever arm l2 carrying stud 13 intermediate its ends and stud 14 at its upper end. Stud '14 extends through slot 5? in plate 54. Knob i5 threaded on stud l4 clamps arm 72 in any desired angular position. Nut 15 and washer ll clamp bushings l8 securely against arm 12. R0- tatably mounted on bushing i8 is eccentric bushing I9. Adjustably secured by screws 89 to eccentric bushing i9 is eccentric rim 8| on the circular periphery of which is formed sheave groove 82 in the plane of groove 79 of sheave 84. Eccentric l9 and eccentric 8! have the same maximum eccentricity so that by relative adjustment of these two parts groove 82 may be concentric with stud E3 or can have an eccentricity thereto equal to the sum of the eccentricities of parts I9 and 8 I.

The tiller rope leading from the air damper control adjustment quadrant is led around under rim'8l in groove 82 and after wrapping partially around sheave 84 in groove i0 is secured to sheave 84 in such a manner that when sheave 84 is rotated the tiller cable wraps or unwraps respectively and thus adjusts the air control synchronously with the coal feed control. As the tiller rope moves with the rotation of sheave 84, it rotates eccencentric idler rim 8! which is adjusted to compensate for the adjustment characteristic of the air control in order that true synchronism is established between the coal feed control and th air control when airm 12 is at the central or normal air ratio position of scale 58 on plate 54. Knob 15 is used to bias the air feed rate against the coal feed rate for various reasons found in the practical operation of industrial stokers.

.It is thus seen that the coal feed and air feed can be simultaneously varied while maintaining the desired fuel-air ratio by manually loosening knob 66 and moving lever arm 64 in the desired direction as indicated on the scale.

It is obviously not likely that either the coal feed adjustment through lever arm 64, cam followers 68, cam 60 and sheaves 2921, 29--3 0, with belt 28 will have a straight line characteristic nor that the air feed adjustment such as shown in Patents 2,116,912, 2,108,873 and 2,149,934 above referred to as connected through a tiller rope to the present invention will have a straight line characteristic matching in a desired ratio the coal feed adjustment. It is therefore desirable to have available the sheave 198l of adjustable eccentricity to adjust within practical limit the air feed control characteristic.

Should it be found in operation that the fuel bed in the furnace gradually builds up or burns down this difnculty can be corrected by loosening knob and manually adjusting lever arm 12 to take up or slacken the air feed adjustment tiller rope connection above referred to and thereby change the fuel-air ratio over the entire range of the control. This latter adjustmentis also very valuable when it is desired to quickly change the depth of fuel bed in the furnace without disturbing the parallelism of the fuel and air adjustments a established by the adjustment of eqcentric sheave 79-8 I.

From the above description of the operation of my device, it is seen that I have provided a means (cam face 60 and cam followers 63) for varying the ratio of the sheave diameters of the V-belt drive to Vary the output shaft speed of the speed changer and thereby vary the rate of coal feed to the furnace, a means (arm 15 of U. S. Patent 2,116,912 or plate 45 of U. S. Patent 2,198,873 or arm 43 of U. S. Patent 2,149,934) for varying the rate of combustion air feed to the furnace, a means (the tiller rope and sheave 84) for connecting said sheave diameter varying means and said rate of combustion air feed varying means for simultaneous operation, a means (lever arm 64) for variably positioning said, connecting means and a means (eccentric sheave 19-8! for adjusting said air rate varying means, whereby a change in the position of said connecting means will not substantially change the ratio of fuel to combustion air feed to said furnace.

Groove 83 of sheave 84 is provided for remote control by tiller rope of coal feed and air feed synchronously. When this means of remote control is used, knob 66 is either left in a loosened condition or removed entirely.

Having thus fully described the mechanism by means of which I have attained the previously stated objects of my invention, it is clear that many variations of the shown constructions are feasible. Therefore, I do not intend to be limited by the constructions shown but desire to preserve the full scope of my invention and I claim:

1. In a coal stoker having means for feeding coal to a furnace, means for feeding combustion air to said furnace, means for driving said coal feeding means, and means for driving said air feeding means, the combination of a continuously variable speed transmission interposed between 7 said coal feeding means and its said driving means, a continuously variable means for varying the rate of air feed to said furnace, means for simultaneously varying in increments of any required size the rate of coal feed and the rate of air feed to said furnace, and means for adjusting said rate varying means whereby a change in coal feed rate will be accompanied by a change in air feed rate without substantially altering the ratio of fuel and air fed to said furnace, said last mentioned means including an idler sheave carried on an adjustably positioned lever arm, said idler sheave comprising an eccentric hub member and an eccentric rim member adjustably secured thereto, each of said members being circular at both its inner and outer diameters and the inner diameter of each of said members being of a circle eccentric with respect to the circle of its outer diameter.

2. In a coal stoker having means for feeding coal to a furnace, means for feeding combustion air to said furnace, means for driving said coal feeding means and means for controlling the rate of combustion air feed to said furnace, the combination of a speed changing power transmission means interposed between said coal feeding means and said means for driving said coal feeding means, said speed changing means comprising two parallel spaced rotatable shafts with a variable sheave diameter V-belt connection between said two shafts, a fixed shaft, means axially slidable on said shaft adapted to vary the ratio of the working diameters of said sheaves, said axially slidable means having a cam face thereon, an

axially fixed cam follower means rotatably mounted on said shaft, said cam follower means being adapted to cooperate with said cam face to vary the axial position of said axially slidable means as the angular position of said cam follower means is varied, means adapting said cam follower means to be angularly positioned in response to a requirement, and means adapting said cam follower means to position said air feed rate controlling means as the angular position of said cam follower means is varied, together with means for adjusting said positioning means for said air feed rate controlling means whereby a change in coal feed rate will be accompanied by a change in air feed rate without substantially altering the ratio of fuel feed and air feed to said furnace, said adjusting means for said positioning means comprising a second non-rotatable shaft, an eccentrically bored hub rotatably carried on said non-rotatable shaft and an eccentrically bored rim adjustably positionable on said hub.

3. The mechanism of claim 2 in which said second non-rotatable shaft is carried on an adjustably positioned lever arm.

4. In a coal stoker having means for controlling the rate of coal feed to a furnace and means for controlling the rate of air feed to said furnace, means for simultaneous control of said coal feed and said air feed to maintain a desired coal feed to air feed ratio, together with means for adjusting said ratio, said coal feed rate controlling means comprising a drive shaft, a driven shaft, a V-belt, a V-belt sheave on each of said shafts, each of said sheaves being separable for relative axial movement of its two belt riding cheeks, one of said sheaves having its left hand half fixed to one of said shafts and its right hand half adapted to slide on said one of said shafts, the other of said sheaves having its right hand half fixed to the other of said shafts and its left hand half adapted to slide on said other of said shafts, a

third shaft secured parallel to said drive and driven shafts. a frame carried on said third shaft and axially movable therealong, means adapting said frame to control the movement of said movable halves of said sheaves axially of said shafts, means biasing said frame axially of said shafts, adjustable means for opposing said biasing means to position said frame, said adjusting means comprising a cam on said frame, a third sheave rotatably mounted on said third shaft, and a cam follower carried on said sheave, said ratio adjusting means comprising a fourth shaft secured parallel to the other said shafts and an idler sheave rotatably mounted on said fourth shaft, said idler sheave comprising an eccentric hub member and an eccentric rim member adjustably secured thereto, each of said members being circular at both its inner and outer diameters and the inner diameter of each of said members being of a circle eccentric with respect to the circle of its outer diameter, said simultaneous control means comprising a rope partially wrapped on said third sheave and on said idler sheave.

5. In a coal stoker having means for controlling the rate of coal feed to a furnace, means for controlling the rate of air feed to said furnace, means for simultaneous control of said coal feed and said air feed to maintain a desired coal feed to air feed ratio, together with means for adjusting said ratio: said coal feed rate controlling means comprising a variable sheave diameter v-belt drive together with a cam and cam follower means for varying the sheave diameters of said drive, a rotatably mounted cam follower carrier and a rope sheave on said carrier; said means for adjusting said ratio comprising a rotatably mounted idler sheave, said idler sheave comprising an eccentric hub member and an eccentric rim member adjustably secured thereto, each of said members being circular at both its inner and outer diameters and the inner diameter of each of said members being of a circle eccentric with respect to the circle of its outer diameter; and said means for simultaneous control comprising a rope secured at one end to said air feed rate controlling means and secured at its other end to said cam follower carrier, said rope being resiliently biased longitudinally in the direction of its said one end, and said rope being wrapped partially around said idler sheave and partially around said carrier sheave, whereby said simultaneous adjustment is accomplished by rotation of said carrier sheave while said desired coal feed to air feed ratio is maintained by the variation in travel of the two ends of said rope as caused by the eccentricity of said idler sheave.

RICHARD C. W'RIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 534,448 McIntyre Feb. 19, 1895 1,971,035 Fulton Aug. 21, 1934-. 1,993,547 Heyer Mar. 5, 1935 2,020,026 Gilpin Nov. 5, 1935 2,315,070 McNaughton Mar. 30, 1943 

